Wolff-Parkinson-White-Syndrome
by Dr. Andrew B. Chung, MD/PhD
10/11/93
Wolff-Parkinson-White-Syndrome (WPWS) involves the potential for paroxysmal tachyarrhythmias secondary to the existence of congenital accessory AV conduction pathway(s) that permit circular reentry activity after an initiating ectopic impulse. This clinical cardiac syndrome has an estimated incidence of 1-3/1000 detectable by random EKG screening of the general population. Approximately 14% will have multiple accessory pathways (Chen et al, 1993). Typically a shortened P-R interval and the presence of "delta" waves are the usual EKG findings for WPWS during normal sinus rhythm. Often such patients will give an asymptomatic history.
When familial, WPWS seems to be inherited in an autosomal dominant fashion (Fomina et al, 1990). There have been reports of phenotypic characteristics associated with WPWS that would suggest a primary disorder of connective tissue (Smolenskiui et al, 1988). These physical findings included high palate (76%), epicanthal folds (20.5%), funnel chest and thoracic kyphosis (30%), and articular hypermobility (51.6%).
The incidence of sudden death associated with asymptomatic WPWS is quite low at an estimated 1 per 1000 patient years of follow-up but this rate depends on the shortest RR interval from electrophysiological testing (Klein et al, 1989). When this RR interval is less than 250 msec there is a 5.6 fold increase in risk of sudden death to 5.6% over 10 years. This EKG measure is very sensitive since approximately 95% of WPWS patients who die suddenly will have had a shortest RR interval of less than or equal to 250 msec. The risk stratification is as follows: Category 1, R-R < 220 msec - definite risk; Category 2, 220 < RR < 250 - probable risk; Category 3, 250 < RR < 300 - possible risk; Category 4, 300 < RR - negligible risk.
In symptomatic WPWS patients the occurrence of ventricular fibrillation (sudden death without defibrillation) was found to be considerably higher (22/101) with the major prognostic indicators being the shortest RR interval during atrial fibrillation and the anterograde effective refractory period of the accessory conduction pathway (Auricchio et al, 1991). History of syncopal or near-syncopal episode(s) has little predictive value for aborted sudden death events.
Thus, when symptomatic with shortest RR interval less than 250 msec, radiofrequency ablation is indicated as a relatively safe means of cure. This method is associated with high success rates (95%) with low mortality (<1%) even when multiple accessory pathways are present (Chen et al, 1993; Saul et al, 1993). Other therapies range from conservative b adrenergic blockage, to which WPWS is often refractory, to more aggressive surgery which carries higher mortality/morbidity.
Auricchio, A., Klein, H., Trappe, H.J., and Wenzlaff, P. (1991). Lack of prognostic value of syncope in patients with Wolff-Parkinson-White syndrome. J. Am. Coll. Cardiol. 17, 152-158.
Chen, S.A., Hsia, C.P., Chiang, C.E., Chiou, C.W., Yang, C.J., Cheng, C.C., Tsang, W.P., Ting, C.T., Wang, S.P., and Chiang, B.N. (1993). Reappraisal of radiofrequency ablation of multiple accessory pathways. Am. Heart J. 125, 760-771.
Fomina, I.G., Logunova, L.V., and Pogrebkova, N.S. (1990). [Heredity in Wolff-Parkinson-White syndrome]. Klin. Med. 68, 61-66.
Klein, G.J., Prystowsky, E.N., and Yee, R. (1989). Asymptomatic Wolff-Parkinson-White. Circulation 80, 1902-1905.
Saul, J.P., Hulse, J.E., De, W., Weber, A.T., Rhodes, L.A., Lock, J.E., and Walsh, E.P. (1993). Catheter ablation of accessory atrioventricular pathways in young patients: use of long vascular sheaths, the transseptal approach and a retrograde left posterior parallel approach. J. Am. Coll. Cardiol. 21, 571-583.
Smolenskiui, V.S., Fomina, I.G., Logunova, L.V., Moreunov, N.B.,
and Narycheva, I.A. (1988). [Phenotypic characteristics of patients
with the premature ventricular excitation syndrome]. Ter. Arkh.
60, 26-28.
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